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(#) Using wakeLock without timeout

!!! WARNING: Using wakeLock without timeout
   This is a warning.

Id
:   `WakelockTimeout`
Summary
:   Using wakeLock without timeout
Severity
:   Warning
Category
:   Performance
Platform
:   Android
Vendor
:   Android Open Source Project
Feedback
:   https://issuetracker.google.com/issues/new?component=192708
Since
:   3.0.0 (October 2017)
Affects
:   Kotlin and Java files
Editing
:   This check runs on the fly in the IDE editor
Implementation
:   [Source Code](https://cs.android.com/android-studio/platform/tools/base/+/mirror-goog-studio-main:lint/libs/lint-checks/src/main/java/com/android/tools/lint/checks/WakelockDetector.kt)
Tests
:   [Source Code](https://cs.android.com/android-studio/platform/tools/base/+/mirror-goog-studio-main:lint/libs/lint-tests/src/test/java/com/android/tools/lint/checks/WakelockDetectorTest.kt)

Wakelocks have two acquire methods: one with a timeout, and one without.
You should generally always use the one with a timeout. A typical
timeout is 10 minutes. If the task takes longer than it is critical that
it happens (i.e. can't use `JobScheduler`) then maybe they should
consider a foreground service instead (which is a stronger run guarantee
and lets the user know something long/important is happening).

!!! Tip
   This lint check has an associated quickfix available in the IDE.

(##) Example

Here is an example of lint warnings produced by this check:
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~text
src/test/pkg/WakelockTest.java:11:Warning: Provide a timeout when
requesting a wakelock with PowerManager.Wakelock.acquire(long timeout).
This will ensure the OS will cleanup any wakelocks that last longer than
you intend, and will save your user's battery. [WakelockTimeout]
    wakeLock.acquire(); // ERROR
    ------------------
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Here is the source file referenced above:

`src/test/pkg/WakelockTest.java`:
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~java linenumbers
package test.pkg;
import android.content.Context;
import android.os.PowerManager;

import static android.os.PowerManager.PARTIAL_WAKE_LOCK;

public abstract class WakelockTest extends Context {
    public PowerManager.WakeLock createWakelock() {
        PowerManager manager = (PowerManager) getSystemService(POWER_SERVICE);
        PowerManager.WakeLock wakeLock = manager.newWakeLock(PARTIAL_WAKE_LOCK, "Test");
        wakeLock.acquire(); // ERROR
        return wakeLock;
    }

    public PowerManager.WakeLock createWakelockWithTimeout(long timeout) {
        PowerManager manager = (PowerManager) getSystemService(POWER_SERVICE);
        PowerManager.WakeLock wakeLock = manager.newWakeLock(PARTIAL_WAKE_LOCK, "Test");
        wakeLock.acquire(timeout); // OK
        return wakeLock;
    }
}
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

You can also visit the
[source code](https://cs.android.com/android-studio/platform/tools/base/+/mirror-goog-studio-main:lint/libs/lint-tests/src/test/java/com/android/tools/lint/checks/WakelockDetectorTest.kt)
for the unit tests for this check to see additional scenarios.

The above example was automatically extracted from the first unit test
found for this lint check, `WakelockDetector.testTimeout`.
To report a problem with this extracted sample, visit
https://issuetracker.google.com/issues/new?component=192708.

(##) Suppressing

You can suppress false positives using one of the following mechanisms:

* Using a suppression annotation like this on the enclosing
  element:

  ```kt
  // Kotlin
  @Suppress("WakelockTimeout")
  fun method() {
     acquire(...)
  }
  ```

  or

  ```java
  // Java
  @SuppressWarnings("WakelockTimeout")
  void method() {
     acquire(...);
  }
  ```

* Using a suppression comment like this on the line above:

  ```kt
  //noinspection WakelockTimeout
  problematicStatement()
  ```

* Using a special `lint.xml` file in the source tree which turns off
  the check in that folder and any sub folder. A simple file might look
  like this:
  ```xml
  &lt;?xml version="1.0" encoding="UTF-8"?&gt;
  &lt;lint&gt;
      &lt;issue id="WakelockTimeout" severity="ignore" /&gt;
  &lt;/lint&gt;
  ```
  Instead of `ignore` you can also change the severity here, for
  example from `error` to `warning`. You can find additional
  documentation on how to filter issues by path, regular expression and
  so on
  [here](https://googlesamples.github.io/android-custom-lint-rules/usage/lintxml.md.html).

* In Gradle projects, using the DSL syntax to configure lint. For
  example, you can use something like
  ```gradle
  lintOptions {
      disable 'WakelockTimeout'
  }
  ```
  In Android projects this should be nested inside an `android { }`
  block.

* For manual invocations of `lint`, using the `--ignore` flag:
  ```
  $ lint --ignore WakelockTimeout ...`
  ```

* Last, but not least, using baselines, as discussed
  [here](https://googlesamples.github.io/android-custom-lint-rules/usage/baselines.md.html).

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